BioMedical Admissions Test (BMAT) Practice Test 2026 - Free BMAT Practice Questions and Study Guide

The process that involves the removal of waste products such as urea from the blood is ultrafiltration. In the kidneys, specifically in the structure known as the glomerulus, blood is filtered under pressure. This process allows smaller molecules, like urea, water, and electrolytes, to pass through the walls of the capillaries into the Bowman’s capsule, forming what is known as filtrate. Larger molecules, such as proteins and blood cells, are retained in the bloodstream because they cannot pass through the filtration membrane.

While filtration is a term that can refer to various processes of separating substances, ultrafiltration specifically describes the mechanism occurring in the kidneys that separates waste products from blood plasma. This precise mechanism is crucial for effectively clearing waste from the bloodstream before it undergoes further processing in the nephron.

Selective reabsorption refers to the process where necessary substances, such as glucose and certain ions, are reabsorbed back into the bloodstream from the filtrate, thus not directly contributing to the removal of waste products. Excretion, on the other hand, is the overall process of eliminating waste from the body, which includes various systems and final steps rather than the initial removal at the kidney level.

Therefore, ultrafiltration is the